class Counter:
    def __init__(self):
        self.__current = 0
    def increment(self):
        self.__current += 1
        
    def value(self):
        return self.__current
    def reset(self):
        self.__current =0
    def __str__(self):
        return (f"__current ={str(self.__current)}")

c = Counter()
c.increment()
print(c)

# accessing private attribute
#AttributeError: 'Counter' object has no attribute '__current'
#print(c.__current) 

# accessing private attribute
print(c._Counter__current) # 